Molds and loading apparatus for molds



March 16, 1965 K. A. ANDERSON 3,

MOLDS AND LOADING APPARATUS FOR MOLDS Original Filed Bay 23, 1960 4 Sheets-Sheet 1 JNVENTOR. :7 5 KAR A LAN Anoaason Atrorney March 16, 1965 K. A. ANDERSON 3,173,171

MOLDS AND LOADING APPARATUSFOR HOLDS Original Filed May 23, 1960 4 Sheets-Shee t 2 Fl KAR N- -mi gtfl a ggon Attorney March 16, 1965 A. ANDERSON 3,173,171

MOLDS AND LOADING APPARATUS FOR MOLDS Original Filed May 23. 1960 i 4 Sheets-Sheet 3 l i, l,

a 6 r I F/ a 7 INVENTOR.

KARL ALLAN Auu asou Attorney March 16, 1965 K. A. ANDERSON MOLDS AND LOADING APPARATUS FOR MOLDS Original Filed May 23, 1960 4 Sheets-Sheet 4 Attorney United States Patent 3 173 171 MGLDS AND LflADiN G XPPARATUS FOR MOLDS Karl AllanAnderson, Park Ridge, 111., assignor to Controls Company of America, Melrose Park, 111., a corporation of Delaware I Original application May 23, 1960, Ser. No. 31,151.

Divided and this application July 1, 1963', Ser. No.

' 13 Claims. (Cl. 185) This invention relates to the apparatus for wrapping a coil and loading the same into a mold as used in the process for encapsulating the space between the end portions of the 'coil. This is a division of my application Serial No. 31,151, filed May 23, 1960 and now abandoned.

Various types of molds have been designed for encapsulating' electrical coils on a mass production scale as shown in my copending patent application Serial Number 840,653, nowsPatent No. 3,084,390 and in Patent No. 3,072,967 issued to Mathews et a1; and assigned to' the assignee ofthe patent application. These molds were designed for an assembly line type of operation wherein a plurality of molds are positioned on a conveyor and advanced in a step-by-step manner. The molds are opened or held open during one step andcoils of the type set forth in copending application Serial No. 857,660 of Fred A. Linn, filed on December 7, 1959 and assigned to the assignee of the present application,

now abandoned, are placed in the molds. The molds are closed in the next step of movement so that the flexible liner positioned within the jaws seals on the periphery of the end flanges of the coil to form a cavity mold in cooperation with the coil bobbin. The resin which is used as the encapsulant is continuously mixed with a hardener immediately prior to using and is poured in the cavity formed by the mold and the flanges of the coil. After the resin and hardener have set, the mold is opened and the coil is removed. Y Because of the extremely abrasive and adhesive nature of the encapsulating compounds, Teflon (tetrafiuoroethylene) was selected for theliner in the mold Even with this type liner, it was still necessary to treat the liner surface after each use to remove any of the encapsulant which had adhered to the liner surface. The liner also had to be replaced periodically because the surface became worn afterlong use.

The primary object of the present invention is to provide a lower cost process for encapsulating coils. 3 Another object of the present invention is to provide a simplified mold of reduced cost and designed for fast servicing if required.

Experiments showed the practicability of using a strip of paper, particularly a strip having an adhesive back 'ing', as a liner for a mold-to prevent contact between the 'encapsulant' and the mold.

achieved a dual advantage in that it provided a good seal between the periphery of the flanges of'the coil bobbin and the liner and also could be readily peeled from the encapsulated coil leaving a textured surface on the coil that proved acceptable without any further working.

The adhesive "backing .Still another object of this invention is to provide" a simplified type mold having a liner which lends itself to multiple casting. e

Still another object of this invention is to provide an expendable liner for a mold at a nominal cost.

' the drawings, inwhichf 3,173,171 Pe te Ma'- 15 1,9555

"ice

A further object of the present invention is to provide an apparatus and process forpreloading a mold at a minimum of time. i

A still further object of the present invention is to provide a mold which can be adapted'to various size coils.

A still further object of this invention is to provide a mold which is simplified in'construction because it is not subjected to the abrasive characteristic of the encapsulant. i i 9 Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the single embodiment shown in FIG. 1 is a front elevation of the mold partly broken away tofshow the spring biasing meansj i FIG. 2 is a side elevation of the mold;

FIG. 3 is a front elevation of the mold in an open position;

FIG. 4 is a side elevation of the loader with the mold in position;

FIG. 5 is a front mold closed;

FIG. 6 is a view of the loader with the mold open and the coil moved part way down; FIG.'7 isa' view o'fthe loader without the mold and thecoil in an upperposit'ionj i VFIG.,8 is a top view of the loader;

FIG. 9 is a back View of the loader; and

FIG; 10' is taken bn'line i010 of FIG. 9 showing the paper positioner.

In an effortto find a low cost molding process, the coilbobbin was wrapped with paper prior to molding aiid found successful. This was first tried in molds of the type disclosed in copen'din'g"application Serial No. 840,653." Further experiments demonstratedthat even better results could be achieved with 'adhesive'backed paper such as masking tape because the paper adhered to thelbobbin providing aseal and alsoserved as an excellent mold release agent-leaving mainstays textured finish. The adhesive paperwas also triedw'ith the' mol d above with success. "It shortly became apparent that the" costof molds could be decreased and rnoldadaptability and fiexibilitylncreasedin 'conjiiriction with the masking tape'approach. The priorfinold was designed to provide a good seal between the coil and liner and prevent leakage of the encapsulant' on the mold. With the adhcsive tap'it is only necessary to insure that tape isst'uck'to' the'flang es of the coil thus eliminatin f lhe elevation of the leader with the costly' backing (Tefionl required previously.

In the mold disclosed herein, the articles to be encapsulated are placed in an adjustable sling with the article contacting only a contoured surface on the mold. The contoured surface provides a downward component of 'forcepressing the coil against the sling, assuring that a' good seal is provided between the coil flanges and the liner; The sling is presently made of Teflon impregnated fiber glass which can be easily cleaned in the event that some of the encapsulant spills on the sling. Plain paper could be used with this arrangement because the seal between the paper and coil is provided by the force of the contoured surface of the mold pressing the coil against the sling. With adhesive type tape, a seal wouldbe'made between the coil flanges and the liner, whether the tape is wrapped on the coil mechanically by a loader described hereinafter or hand wound. The mold aids the seal between the flanges of the coil and the paper and locates the coil with respect to the conveyor when the mold is returned to the assembly line. While it may be feasible to Wrap coils by hand, it is better to do it automatically on a coil loader of the type shown in FIGS. 4-10. In the prior patent application Serial No. 840,653, the coil was removed automatically while the mold remained on the assembly line. It has been found better to unload and load oh? the conveyor, with the above loader since the adhesive backing of the masking acts as an excellent release agent for removing the tape from the encapsulated coil leaving a smooth textured finish.

As seen in FIGS. 1 through 3, the mold includes a pair of brackets 10, pivoted on rods 12, 12 which are secured to base 14. Replaceable jaws 16, 16 are secured to the brackets by bolts 20 and a flexible sling 21 is suspended between and secured to the jaws by clips 22 and screws 24. The brackets are biased towards each other by compressed springs 26 in holes 28 forcing caps 30 against the base. The mold is opened by the coil loader and a coil of the type mentioned above is wrapped with a paper liner and placed on the sling. The mold is closed and the interior surfaces 34 of the jaws engage the upper periphery of the flanges of the coil forcing it downward within the sling. This force can be varied by adjusting screws 32, which also serve to vary the gap between the jaws to accommodate different size coils. To set the mold for a specific coil, the coil should be placed in the sling and clips 22 loosened. The sling is then pulled so that the coil seats against the jaws and the clips tightened. Screws 32 can then be adjusted to provide the desired sealing pressure.

The mold is positioned manually on the coil loader in the closed position (FIG. 5) with pins 38 on levers 39 projecting through holes 36. The mold is opened when crosshead 42 is moved upward by the actuation of double acting air cylinder (not shown) connected to bolt 44 on the crosshead. Cam 46 (FIG. 9) mounted on the back of the crosshead acts on cam rollers 50 on levers 52 to rotate shafts 41 in opposite directions and levers 39 mounted on shafts 41 move outward causing pins 38 to open the mold.

When the crosshead reaches the upper position, a coil 53 (shown dotted FIG. 7) is manually positioned on coil shaft 54 which is shaped to conform to the central opening in the coil bobbin. A paper tape 56 is pulled across platens 58 either manually or mechanically and placed between guide pins 69. The tape is out in a length suflicient to enclose the coil with its center located approximately below the axis of coil shaft 54. The crosshead is moved downward by reversing the motion of the air cylinder pushing the coil with the paper downward between tape rollers 62. The tape rollers are mounted on rocker arms 64 which are pivoted on shafts 66 and are biased into engagement with the periphery of the flanges on the coil bobbin by spring 67 connected to levers 82 on shafts 66. The tape rollers wrap the paper around the periphery of the flanges of the coil as the coil is moved downward with the crosshead. When an adhesive type tape is used, the pressure of the rollers on the periphery of the flanges is suflicient to seal the tape to the coil. When plain paper is used to enclose the coil, the tape rollers hold the paper firmly in place around the coil while the crosshead is moving downward. Near the end of the downward movement of the crosshead, the corners of block 74 mounted on the crosshead will engage arms 64, rotating them outward until latch rods 70 biased by springs 68 snap into notches 76 in the rocker arms to hold the tape rollers in an outward position. Immediately before the crosshead reaches the end of its downward movement, the coil will engage the sling in the mold and at approximately the same time, the rollers 50 move inward on cam 46 allowing the mold to close on the coil.

The tape is cut in lengths longer than required to enclose the coil to allow for any misalignment in centering the paper. The ends of the paper extending above the mold are folded back into clips 22 by actuating paper spreader 78, leaving an opening in the top of the mold for the admission of the encapsulant. As seen in FIGS. 9 and 10, the paper spreader includes a pair of plates eccentrically mounted on shafts 82, 84 which are operatively connected by gears 86, 86. Shaft 82 is extended (FIG. 10) to carry gear 90, which operatively engages rack 2. When the crosshead reaches the end of its downward movement, a switch (not shown) is tripped, either by the slider or manually, to actuate solenoid 94, pulling rack 92 upward and compressing spring 96. Gear rotates shaft 82 clockwise (FIG. 9) and shaft 84 counterclockwise, moving plates 30 into a horizontal plane and pushing the ends of the tape into the clips on the mold. Since an adhesive tape would adhere to the flat surface of the plates, pins 96 are provided to engage the paper, thereby reducing the surface area engaging the tape so that the clips will hold the tape when the spreader is closed. Once the paper is secured in the clips, the solenoid is released, allowing spring 96 to pull the rack downward and rotate the plates 89 back to a vertical position. The clips will hold the ends of the paper clear of the opening in the top or" the mold for the admission of the encapsulant.

The molds are then manually removed from the loader and another mold placed on the loader. The molds can be mounted in pairs on a common base which requires a double coil loader to load the molds. When the base is positioned in the conveyor, the molds will be properly aligned with the encapsulant injectors. After encapsulation, the molds are removed from the conveyor and again placed on the loaders. The air cylinder is actuated moving the crosshead upward to open the mold as described above. The encapsulated coil is manually removed from the mold and a coil bobbin placed on the coil shaft. As described above, the tape rollers are held in an outward position by latch rods 70. It can be seen in FIG. 7 that if the latch rods were allowed to return to a closed position, after the crosshead has moved to a lower position, the tape spreader and coil shaft could not clear the rollers when the crosshead is moved upward.

- When the coil shaft has moved far enough upward to clear the rollers, the upper surface 81 of block 74 will engage crosspiece 83 which is connected to latch rods 70 pulling the latch rods out of notches 76 in the rocker arms. Spring 67 will pull the tape rollers towards each other until latch rods 70 engage notches 75.

In the prior type molds, Teflon was used for the liner to provide a positive seal between the coil and the liner and because the encapsulated coil could be easily removed from the mold. In the present sling type mold, a disposable liner is used in place of the semi-permanent Teflon liner in order to reduce the cost. It has been found that the adhesive on the back of the tape also provides an excellent release agent for easy removal of the liner from the coil after encapsulation, leaving a highly acceptable textured surface on the coil. The. sling acts only to support the coil and is made of Teflon impregnated fiber glass because'of its tough and durable characteristics and because it requires very little maintenance. The sling also lends itself readily to a variety of shapes, increasing the over-all versatility of the mold. It is conceivable to use custom made tape having a specific trademark printed thereon which would be left on the surface of the coil after the tape has been removed.

The coils could be encapsulated by a manual process using the adhesive type tape. Wrapping the coil tightly with the tape will provide a completely sealed cavity into which the encapsulant is poured. The adhesion of the tape to the coil is suflicient to hold the encapsulant, since the encapsulant is only poured into the mold and no pressure is exerted against the liner. After the enp u nt h s s t t e ta ca be easily peel d rom the coil because the adhesive on the tape acts as a release agent, leaving an attractive textured finish on the coil, which q esl qtewq h is Although but a single embodiment of the present invention' has been illustrated and described, it will be ppa ent to. hose Skilled. in the art that various changes and modification may be made therein'withoutdeparting from the spirit of the invention or from the scope of the appended claims.

I claim:

1. A device for loading a coil into a mold comprising, means for holding a mold in coil receiving position, means for holding the coil for movement toward the mold, means for supporting a strip of liner material for movement with the coil into the mold, means for wrapping the strip about the periphery of the coil prior to the entrance of the coil into the mold, and actuating means for moving the mold to a molding position in which the mold will seal the strip to the coil.

2. A loading device for placing coils of the type having end members, the space between which is to be encapsulated, into a mold having movable jaws comprising, a frame, a member movable with respect to the frame, means for supporting the mold on the frame, said movable member including means for controlling the position of the mold support means thereby opening and closing a mold supported thereon in response to movements of the movable member, means for supporting one of the coils on the movable member and means for supporting a disposable liner in position to be carried into the mold by the movement of the coil into the mold, whereby the mold is closed when the article supporting means is within the mold sandwiching the liner between the coil and the mold, and the mold is opened when the article supporting means is moved out of the mold.

3. A device according to claim 2 wherein the liner is comprised of a strip of paper provided with an adhesive backing and wherein the mold supports the coil for reception of an encapsulant.

4. A device for loading coils into a mold comprising, means for holding a mold in position to receive a coil, said mold holding means being movable to open and close the mold, means for supporting a coil for movement into and out of the mold, said coil supporting means controlling the opening and closing of the mold, means for supporting a strip of paper in the path of the coil supporting means so that the paper will be carried into the mold by the movement of the coil supporting means toward the mold, means for wrapping the paper about the periphery of the coil as the coil'supporting means moves toward the mold, said wrapping means being biased to an operative position, means for latching the wrapping means in an inoperative position when the coil has been moved into the mold, said coil supporting means allowing the mold to close when the coil is positioned in the mold, and means for spreading the paper at the top of the coil for the admission of encapsulant, said wrapping means being released from the latching means when the coil supporting means is moved to the initial position.

5. A device according to claim 4 wherein the strip of paper is provided with a mold release agent and the wrapping means seals the paper to the coil as it is moved into the mold.

6. The combination with a mold having movable jaws and a flexible member supported between the jaws for reception of a coil of the type having end flanges the space between which is to be encapsulated, of means for loading the mold with a prewrapped coil comprising means for holding the mold in coil receiving position, means for supporting a coil for insertion into the mold, a strip of paper positioned in the path of the coil so that it is moved into the mold by the movement of the coil into the mold, and means for wrapping the paper on 6 r the coil as the coil movesthe paper into the mold, said mold holding means allowing themold to close on the coil to sandwich the paper between the coil and the liner, and-means for formingan opening in thetop of I the wrapped coil for the admission: of an encapsulant.

7. The combination according to claim'6 including means, for latching the wrapping means in an inoperative position for the return motion of the coil supporting means S'Ql L Q I' upport ng means e a g the tch n means when in position to receive another coil.

8. A mold for encapsulating an article having end portions the space between which is to be encapsulated comprising, movable mold sections, a single-use liner comprised of a substantially flat strip of paper having an adhesive surface, said liner being movable independent of said mold sections to wrap the article by having the adhesive coated surface of said liner engage the peripheries of the end portions to thereby form a cavity defined by the end portions and said liner, actuating means to move said mold sections into a pressing contact with the other side of said liner after the article has been wrapped by said liner to thereby press said liner into sealing engagement with the peripheries of the end sections before said cavity is filled with an encapsulant, and means for moving said sections out of said pressing contact after said cavity is filled by the encapsulant to permit removal of the article and said liner, the adhesive acting as a release agent for removing said liner from the encapsulated article.

9. A mold for encapsulating an article having end portions the space between which is to be encapsulated comprising, a flexible single-use liner having an adhesive coated side, said liner being movable to wrap the article by having said adhesive coated side engage the peripheries of the end portions to thereby form a mold cavity defined by the end portions and said liner, actuating means to move said mold sections into a pressing contact with the other side of said liner to press said adhesive coated side into a sealing contact with the peripheries of the end portions before said cavity is filled with an encapsulant, means for moving said sections out of said pressing contact after said cavity is filled by the encapsulant to permit removal of the article and said liner, said liner being removable from the article after it has been encapsuled and said adhesive acting as a release agent when said liner is removed.

10. A mold according to claim 9 wherein said liner comprises an adhesive coated paper.

11. Apparatus for encapsulating the section between the flanges of a coil, comprising: a mold having mold sections movable between open and molding position; positioning means for positioning a strip of flexible material in spaced relationship in respect to the mold sections; wrapping means responsive to relative movement between the coil and the wrapping means to bring one side of the strip in contact with the peripheral edges of the flanges to thereby form a cavity defined by the flanges and the strip, means for moving the mold sections into the molding position in which the mold sections are in pressing contact with the other side of the strip and are operable to maintain the strip in sealing engagement with the peripheries of the flanges while the cavity is filled with an encapsulant; and means for moving the mold sections to the open position after the cavity has been filled with the encapsulant to permit removal of the coil and the flexible strip.

12. The combination according to claim 11 wherein said mold sections comprise two jaws and a flexible member supported between said jaws.

13. Apparatus for encapsulating the section between the flanges of a coil comprising: a mold having a mold opening and mold sections movable between open and molding positions, positioning means for positioning a strip of flexible material across the mold opening; wrapping means positioned between the mold opening and the 3,173,171 7 8 strip and operable to bring one side of the strip into after said cavity has been filled with the encapsulant to contact with the peripheral edges of the flanges to thereby permlt e oval of t e C011 and the flexible strip. form a cavity defined by the flanges and the strip; means for moving the mold sections into the molding position References Clted the me of thls patent in which said mold sections are in pressing contact with 5 UNITED STATES PATENTS 4 the other side of the strip and are operable to maintain 516,638 Niningef M 13, 1894 said strip in sealing engagement with the peripheries of 1,810,156 Brandenburg June 16, 1931 the flanges while the cavity is filled with an encapsulant; 2,210,509 Strauch Aug. 6, 1940 and means for moving said sections to the open position 2,690,634 Kefchfel et 1954 

1. A DEVICE FOR LOADING A COIL INTO A MOLD COMPRISING, MEANS FOR HOLDING A MOLD IN COIL RECEIVING POSITION, MEANS FOR HOLDING THE COIL FOR MOVEMENT TOWARD THE MOLD, MEANS FOR SUPPORTING A STRIP OF LINER MATERIAL FOR MOVEMENT WITH THE COIL INTO THE MOLD, MEANS FOR WRAPPING THE STRIP ABOUT THE PERIPHERY OF THE COIL PRIOR TO THE ENTRANCE OF THE COIL INTO THE MOLD, AND ACTUATING MEANS FOR MOVING THE MOLD TO A MOLDING POSITION IN WHICH THE MOLD WILL SEAL THE STRIP TO THE COIL. 